*{
  margin: 0;
  padding: 0;
}
#box{
  width: 200px;
  height: 200px;
  border: 1px solid #000;
  margin: 200px;
  position: relative;
  float: left;
}
#big{
  width: 230px;
  height: 230px;
  border: 1px solid #000;
  overflow: hidden;
  position: absolute;
  top:0;
  left : 200px;
  display: none;
}
#small{
  position: relative;
}
#bigImg{
  position: absolute;
  left: 0;
  top: 0;
}